OpenOffice.org 2.4.0 is a free, open source alternative to Microsoft's Office application suite. It is fantastic if you need basic office applications such as a word processor or spreadsheet at no cost. However, large organisations and power users may be disappointed by its lack of features and support. Read the full review here.

You're lucky. Not all my customers and business partners can read PDF or ODT. Some can only read DOC and RTF. There are even customers that you either have to hand in the docs or send by fax / regular mail. Not all business partners have top-notch computers, there are cases where the company is so family-oriented and old that they don't have a single computer. This is the truth.

Handing in the printed docs or sending a fax is preferable to sending a .doc or .rtf. If you send them an easily edited document you might as well send them a proposal with blank numbers and let them chose what price they want to pay.
That's a bit exaggerated but I think that's what the OP as alluding to.